Project Summary Recently developed Multidomain Peptides (MDP) can be triggered to self-assemble into nanofiber hydrogels. Given the simplicity and versatility offered by these short chain amino acid sequences, the physical and biological responses can be tuned. Incorporation of cell degradation sites into the amino acid backbone allow for peptide hydrogels to be broken down by infiltrating cells. Similarly, engineering cell binding domains into the peptide sequence, offer a method to allow cell adhesion and proliferation. Together, mixtures of degradable and non-degradable peptides will allow time-dependent enzymatic breakdown with cellular infiltration. Hydrogels can be easily aspirated into a syringe and delivered via needle, with mechanical recovery. This will allow cytokines and growth factors to effectively be delivered into biological scaffolds or pathologic lesions - such as hollowed out teeth during a root canal. Any procedure or implant (including a root canal) will induce an inflammatory reaction. While others have tried to obviate this inflammatory response, we aim to modulate the infiltrating immune cells' response to one of healing as opposed to chronic inflammation/implant rejection. This has been demonstrated with specific cytokines that guide inflammatory cells to a healing and resolution phenotype. While not attempted with dental regeneration, prior studies have shown efficacy in models including nerve regeneration and vascular tissue engineering. Further, addition of a molecule that aids in blood vessel formation will help in creating living tissue. These additives will be tested in vitro with immune cells, cells from blood vessels and dental stem cells. The work will culminate with in vivo application of these cytokine/ growth factor loaded gels - where inflammatory cells will be guided to resolve inflammation, infiltrating cells will develop blood vessels and replace the nanofiber scaffolding with native living tissue. This project is organized into 3 aims. Aim 1 will determine the degradation of MDP, and loading and release of cytokines / growth factors. Aim 2 will elucidate the cellular behavior of immune cells, blood vessel cells and dental pulp stem cells in loaded MDP nanofibers. Aim 3 will determine biocompatibility and immune response of loaded MDP nanofibers in an animal model of wound healing and dental pulp regeneration. While showcasing applicability for dental regeneration, loaded peptide scaffolds can be tailored to a variety of other applications for tissue engineering and translational medicine.